Precalculus (6th Edition)

Chapter R - Review of Basic Concepts - R.1 Sets - R.1 Exercises: 18

Answer

The set is infinite.
10 is an element of the set.

Work Step by Step

The even natural numbers are $2, 4, 6, 8, 10, 12, ...$.
The set has no bound on the right so the number of elements is infinite.
Note that 10 is an even natural number so it is an element of the given set.